Positioning apparatus

Abstract

In case that some trouble occurs in exhaust pump or in pipe, internal pressure of groove comes closer to atmospheric pressure owing to leak-in of air, because the groove adjoins groove opened to atmospheric air. However, the internal pressures of grooves are maintained at negative value. Thus, difference in pressure between the top and bottom surfaces of moving block is generated. Further, the gap between the moving block and the intermediate block decreases. Consequently, the deterioration in the degree of vacuum in the process chamber can be retarded. During retarded time, measures to protect an object to be processed, such as operation of tightly sealing the object can be taken. Further, in case that the system recovers, time required to operate turbo-molecular pump for sucking the inside of the process chamber is reduced to a short time. Therefore, the processing can be quickly resumed.

1. A positioning apparatus, comprising:
 a process chamber exposed under reduced pressure;  
 a first casing having a first guide face that has a first opening communicating with inside of the process chamber;  
 a moving block movable in at least one direction and opposed to said first guide face through a predetermined gap;  
 a second casing including: 
 a second guide face being on the other side of the moving block via the moving block, and guiding in a state that the second guide face is opposed to the moving block through a predetermined gap; and  
 a decompression chamber whose internal pressure is lower than a pressure of an outside of the process chamber;  
 
 a first differential pumping seal including a plurality of stages, provided between the first casing and the moving block to surround the first opening and sealing between an inside of the process chamber and an outside of said process chamber, wherein a pressure of the outside of the process chamber is higher than that of the inside of the process chamber; and  
 a seal mechanism for maintaining an inside of the decompression chamber at a pressure that is lower than that of an outside of the decompression chamber,  
 
     wherein a stage of the first differential pumping seal, which is most far from said process chamber, and the inside of the decompression chamber are connected to a same exhaust source. 
   
   
     2. The positioning apparatus according to  claim 1 , wherein the moving block is supported with respect to said first casing and said second casing by a hydrostatic bearing or a magnetic bearing. 
   
   
     3. The positioning apparatus according to  claim 2 , wherein the hydrostatic bearing or the magnetic bearing are adjustable to support the moving block with respect to said first casing and said second casing. 
   
   
     4. A positioning apparatus, comprising:
 a process chamber exposed under reduced pressure;  
 a first casing having a first guide face that has a first opening communicating with inside of the process chamber;  
 a moving block movable in at least one direction and opposed to said first guide face through a predetermined gap;  
 a second casing including: 
 a second guide face being on the other side of the moving block via the moving block, and guiding in a state that the second guide face is opposed to the moving block through a predetermined gap; and  
 a decompression chamber whose internal pressure is lower than a pressure of an outside of the process chamber;  
 
 a first differential pumping seal including a plurality of stages, provided between the first casing and the moving block to surround the first opening and sealing between an inside of the process chamber and an outside of said process chamber, wherein a pressure of the outside of the process chamber is higher that that of the inside of the process chamber; and  
 a seal mechanism for maintaining an inside of the decompression chamber at a pressure that is lower than that of an outside of the decompression chamber,  
 wherein control device controls the gap between the first guide face and the moving block in accordance with an operating condition of at least one of the first differential pumping seal and the seal mechanism.  
 
   
   
     5. The positioning apparatus according to  claim 4 , wherein
 the seal mechanism is a second differential pumping seal which is provided on opposed faces of said second guide surface and said moving block, wherein  
 the second differential pumping seal seals between the inside of the decompression chamber and the outside of the decompression chamber, and wherein  
 the control device controls an internal pressure of piping, through which the first and second exhaust seals are connected to an exhaust sources.  
 
   
   
     6. The positioning apparatus according to  claim 4 , wherein
 the first differential pumping seal has two or more stages, wherein  
 the second differential pumping seal has a single stage, and wherein  
 one of the stages of the first differential pumping seal, which is most far from said process chamber, and said second differential pumping seal are connected to a same exhaust source.  
 
   
   
     7. The positioning apparatus according to  claim 5 , wherein
 the first differential pumping seal has two or more stages, wherein  
 the second differential has a single stage, and wherein  
 one of the stages of the first differential pumping seal, which is most far from said process chamber, and said second differential pumping seal are connected to a same exhaust source.  
 
   
   
     8. The positioning apparatus according to  claim 4 , wherein the moving block is supported with respect to said first casing and said second casing by a hydrostatic bearing or a magnetic bearing. 
   
   
     9. The positioning apparatus according to  claim 5 , wherein the moving block is supported with respect to said first casing and said second casing by a hydrostatic bearing or a magnetic bearing. 
   
   
     10. The positioning apparatus according to  claim 8 , wherein the hydrostatic bearing or the magnetic bearing are adjustable to support the moving block with respect to said first casing and said second casing.